thereby removing it from the collodion or gelatin film. This
leaves us now with a completed negative for general photographic
purposes
Line Negalives.—The commonest form of photo electric work
which we see is known as line work, that is, reproductions of pen
and ink drawings, intense black and white effects and some
special crayon work adapted to the process. Examples of such
work may be seen in every newspaper, Judge, Puck and others
abound with drawings reproduced by this process and, if the
artist be a good one, such reproductions are very effective for illus
trative purposes, for example, C. D. Gibson's work.
The copy--the drawing--as it conies to the engraver is gen
erally from one-half to twice-again as large as the illustration is in
tended to be. In fact, it is made larger as the negative gains in in
tensity and sharpness by the reduction. The copy is mounted on the
copy board and the whole placed on the frame for supporting the
camera and board and the camera focussed. The camera used for
such purposes. differs from the ordinary camera in the extreme
length of bellows which enables it to be used for reducing, copy
ing, and enlarging. Now, as the reproduced drawing must
be of given size, say of a width equal to that of two columns
of a newspaper, the engraver moves the camera until the image
which he sees on the ground glass screen is sharply defined
and about four or four and a quarter inches in width,—the desired
size. Having focussed the copy and inserted suitable stops in the
lens to obtain better definition, the operator coats a glass plate
with collodion containing halogen salts, sensitizes it by immersion
for a few minutes in a bath of silver nitrate, places it in a plate
holder, film side forward, inserts the holder in the camera and
then exposes the plate.
The plate is now ready to be developed and fixed after which
it must be intensified. An ordinary negative, for printing on
metal, is worthless, as the dark parts permit too much light to pass
through them, therefore intensification, which renders the dark
portions opaque, is necessary. Intensification may be effected by
flowing the negative with a combined solution of copper sulphate
and potassium bromide until the film becomes white, washing,
and then flowing it with silver nitrate solution until it all is black
ened, this operation being repeated until the lines appear sharp
and clear. Additional intensity is sometimes desired; it is gained